Add test case for #119014

Author: dianqk

tests/codegen/enum/enum-early-otherwise-branch.rs

@@ -0,0 +1,25 @@
+// compile-flags: -O -Zmir-opt-level=3 -Zunsound-mir-opts
+
+#![crate_type = "lib"]
+
+pub enum Enum {
+    A(u32),
+    B(u32),
+    C(u32),
+}
+
+#[no_mangle]
+pub fn foo(lhs: &Enum, rhs: &Enum) -> bool {
+    // CHECK-LABEL: define{{.*}}i1 @foo(
+    // CHECK-NOT: switch
+    // CHECK-NOT: br
+    // CHECK: [[SELECT:%.*]] = select
+    // CHECK-NEXT: ret i1 [[SELECT]]
+    // CHECK-NEXT: }
+    match (lhs, rhs) {
+        (Enum::A(lhs), Enum::A(rhs)) => lhs == rhs,
+        (Enum::B(lhs), Enum::B(rhs)) => lhs == rhs,
+        (Enum::C(lhs), Enum::C(rhs)) => lhs == rhs,
+        _ => false,
+    }
+}